This chapter describes the recent developments in the field of psychiatric pharmacogenetics. Most pharmacogenetic studies of antidepressants have focused predominantly on treatment response, perhaps also due to the fact that most current antidepressants are well tolerated and fairly safe. Pharmacotherapy is the treatment of choice for psychotic symptoms of mental conditions such as schizophrenia, bipolar disorder, and psychotic depression. Antipsychotic drugs are traditionally divided into two groups: typical (first-generation) antipsychotics, with strong affinity for the dopamine receptor, and atypical (second-generation) antipsychotics, with multiple receptor targets. Anticonvulsant drugs are widely used in the management of behavioral disorders, including bipolar disorder, mood disorders, and impulse control disorders. While psychiatry has entered the new area of pharmacogenetics, it is important to remember that this new technology will only provide additional information on one aspect of the complex and personal history of psychiatric patients.